Conventional cattle feeds such as corn and alfalfa often fail to provide sufficient energy for cattle, especially lactating dairy cattle during periods of heavy milk production. Feed containing a high proportion of corn also has a tendency to depress the milk fat content of the milk produced by such cattle. Fat is an excellent energy source, and it is known that if the proportion of fat in cattle food is increased, lactating dairy cattle produce high milk yields without draining their reserves of body fat and without diminishing the proportion of milk fat in the milk produced.
However, it has been found that if the proportion of fat in the diet of cattle exceeds about 5% of the total feed solids, the feed has toxic effects upon the microorganisms in the rumen of the cattle. It appears that fat reduces the growth rate or even kills certain microorganisms which digest fiber in the cow's rumen, thereby lowering fiber digestibility. This deleterious effect on the cow's rumen is particularly true of unsaturated fats. Although the decreased fiber digestion in the rumen is partially compensated by greater fiber digestion in the lower parts of the alimentary canal, the total energy derived is less than that resulting from more complete microbial digestion in the rumen.
There has been a continuing need for new dietary supplements for animal feed which can be fed to ruminant animals without interfering with the rumen microorganisms.
U.S. Pat. Nos. 4,642,317; 4,826,694; 4,853,233; and 4,909,138 describe the incorporation of insoluble fatty acid salts in ruminant feed as a means of increasing the fat content of the feed without deleteriously affecting the ruminant digestion cycle. A feed additive such as fatty acid calcium salt functions as a rumen bypass product, and is subsequently metabolized in the abomasum or small intestine of the ruminant.
Another important aspect of animal husbandry is the provision of carbohydrate-containing supplements as an energy source in animal diets. Molasses is especially valuable as a feed supplement since it furnishes a supply of fermentable carbohydrate for the development and maintenance of intestinal microflora, particularly in the rumen which assists ruminants in utilizing cellulosic roughages.
A disadvantage of molasses-type carbohydrates is high palatability which causes animals to consume excessive feedstuff. Rigid animal feed blocks have been developed as a means of controlling the rate and quantity of feed consumption by animals.
Feedstuff in animal block form also has other advantages, such as permitting free choice feeding and reducing the labor required for mixing carbohydrates and other nutrient supplements in the feed ration of cattle, sheep and other domestic animals.
References which describe the production of animal feed block compositions include U.S. Pat. Nos. 3,246,336; 3,961,081; 4,160,041; 4,265,916; 4,631,192; 4,708,877; 4,729,896; 4,851,244; 4,994,282; 5,068,114; and publications cited therein.
Accordingly, it is an object of this invention to provide a fatty acid salt composition which can function as a rumen bypass animal feed supplement, and permit a beneficial increase in the dietary fat content of the feed.
It is another object of this invention to provide a fatty acid salt dietary supplement composition which contains a carbohydrate and one or more additional biologically active nutrient or medicament ingredients.
It is a further object of this invention to provide a fatty acid salt composition which is in the form of an animal feed block for controlled free choice feeding of dietary supplements to ruminants and other animals.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.